The common swift isn’t common at all.  It can stay in flight mode for 10 months and nap while flying.

Curious about common swifts and their capacity to stay in flight, University of Lund biologist Anders Hedenstrom and his group captured swifts and clipped them with tiny data recorders.

Data recorders used had to be ultra light at four hundredths of an ounce as swifts themselves are light as a feather weighing only one and a half ounces. Using these micro devices help track movements without putting a burden on the animal.

The device was built to sense light as well as track movements. Moreover, it can help monitor the bird’s location using the sun’s movement.

For a year, starting 2014, the group recaptured the birds clipped with the device. Initial data showed that during the winter season, the flock headed to and stayed on the west side of Africa.

But the most interesting data culled was that three of the birds never set foot on land and was always in flight. A few others took very short breaks from flying and this occurred at night time. Still, almost all the swifts were flying almost 100 percent of the time and would pause only if they are going to nest.

This behavior could be the reason why there aren’t any roosts in Africa. The birds would rather stay in flight, except when nesting.

For the past 10 decades, Sweden has captured 50,000 swifts, banded them with identification (usually around one leg), and released afterward.

Another interesting data was that the birds habitually ascended at distances of one and a half miles. This happens usually during twilight.

According to Hedenstrom, the birds zoom upwards to get the sleep they need at that instant when they are already gliding. It is still mystifying how these swifts manage to fly constantly despite the seeming lack of sleep. There are other birds, however (frigate birds) that can sleep while on flight according to a study.

His team is optimistic that they too can extract data on how swifts manage to sleep while flying or gliding. At the moment, an ultra light and tiny device that can record the birds’ brain activity while in flight has yet to be developed.

With continuous technological advancements in super tiny tracking and recording devices, it won’t take long for this team to realize their next goal of studying sleep behaviors among swifts.